Pulmonary artery or infra-coronary aortic bands were placed in young miniature swine to induce right or left ventricular hypertrophy. As the animals mature and develop ventricular hypertrophy and/or heart failure they are being studied for changes in gross and microscopic ventricular morphology as well as changes in ventricular function and regional coronary blood flow. Swine were chosen for the experimental animals because: 1) at maturity the animals weigh 50 to 60 kg, about the same as an adult human. 2) The lack of epicardial collateral coronary arteries in swine makes their coronary circulation similar to that of man.